Safety catch for hoist conveyeances



yJuly 5, 1938. F. o. JAECKEL 2,122,943

SAFETY CATCH FORl HOIST CONVEYANCES Filed Aug. 11, 195s Franz Unto Jaeclel Patented July 5, 1938 UNITED STATES PATENT OFFICE Franz Otto Jaeckel, Johannesburg, Transvaal, Union of South Africa.

Application August 11, 1936, Serial No. 95,474 'In the Union of South Africa August 15, 1935 is claims.

The present invention relates to `safety catch mechanism provided in hoisting systems for stopping and holding the conveyance in the event of the hoist rope breaking or other dangerous conditions of a similar nature occurring; such mechanism being of the kind which brakes the conveyance by frictional engagement with the conveyance guides or like xed parts.

The object generally of the invention is to provide safety catch mechanism which will operate satisfactorily under various conditions of danger which are likely to occur, particularly in minehoist systems.

The main object of the invention is to provide safety catch mechanism on the conveyance which will operate as soon as the hoisting rope is overstressed so as to brake the conveyance and to release therope, and so as to prevent, if possible, the rope being stressed to braking point.

Accordingly if the car is accidentally dangerously overloaded and the rope is thus overstressed, the rope will be released and the car Will be simultaneously braked; also if the winding rope should break while the conveyance is descending and the loose end of the length remaining attached to theconveyance should catch in the shaft,it will be prevented from stopping the conveyance suddenly lor pulling off the brake.

Another `object of the invention is to exert the braking pressure evenly overa large Ybrake shoe area; thereby bringing the conveyance to rest with certainty `but sufficiently gradually to avoid dangerous shocks to persons travelling in the conveyance, and thereby also making the safety catch mechanism suitable for use with metal guides. The Acommonly employed safety catches are suitable for use only with wooden guides.

An example of the invention is shown in the accompanying drawing which is a `perspective view.

The conveyance shown is `an ore skip working -in a vertical mine shaft equipped with fixed `rguide rails indicated by 2, 2. The skip comprises the body 3 mounted in a frame. Thetop member of the frame consists of the spaced vertical plates 4, 4. The side members of the frame include slipper sections 5, 5 and 6, E, the sections 5, 5 being fixed to the ends of the plates `4, 4; and both sections 5, A5 and 5, 6 slidingly engaging the guides 2, 2. The side members of the frame 'also include castings :'I, l', which are interposed between and connect the slipper sections 5 land 6, and which `are further described hereafter.

The winding rope, indicated by 8, is attached to the king bolt 9; at the lower end of which a cross head I0 is retained by the nut II and lock nut I2. Between said cross head I0 and a collar I3 slipped onto the king bolt there extend a tubular distance piece I4 and a compressed spring I5. The distance piece I4 limits the extent to which the cross head ID and the collar I3 can approach one another, and 1t encloses the spring I5. It also provides the king bolt assembly with a smooth external surface for engagement with the split tubular guide I6, I6 which is fixed to the cross beam to guide the'king bolt assembly for vertical movement relatively to the skip.

The skip issuspended from the collarV I3 by means of levers I1, I1 and I8, I8 at opposite sides of the collar, each consisting of a pair of lever arms I1, 18 respectively. Each such lever is pivotally mounted on a bearing pedestal I9 secured to a channel member 2|) fixed between the plates 4, 4 of the cross beam.. The collar ends of the levers Il, I8 seat in pockets 2I, the bearing surfaces of which are provided by pins 22 inserted transversely into the collar at the opposite sides thereof. The outer end of each lever I1, I1 and I8, I8 is supported by engagement withpintles 23 extending transversely from a cap 24 which in turn is supported on a compression spring 25, resting on a shelf 26 fixed to the cross beam 4, 4. Extending through the cap 24, the spring 25 and the shelf 26 is a slidable rod l2l provided below the cap with a collar 28 which is normally spaced somewhat away from the cap. Said rod is further provided with a transverse pin 29 which rests on the shelf 26 and soY supports the rod, but which can be sheared oi Yagainst the shelf upon the rod being forcibly driven downward. The lower end 21a of the rod, below the pin 29 is made adjustable in length by means of -a turnbuckle device 30.

The king bolt 9 shown is of square section as is usual to counteract the tendency of the rope to twist one way or another as the conveyance is being raised or lowered. The cross head I0 has a corresponding square hole for the bolt; and is held against'rotation by a -Ipair of ears 3I engaging the slots 32 between complemental parts of the split tubular guide I6, I6.

Considering now the brake mechanism proper, .each side o-f each casting .l embodies a number of hydraulic brake cylinders 33 arranged in a row parallel with the shaft guides 2 with their axes transverse to the side faces 34 of said guides 2. The rams 35 of the several cylinders forming each vertical row are all connected to a,

brake shoe plate 36 faced with brake fabric 31 and positioned sufficiently close to Ithe guide side faces 34 to engage the latter without undue idle movement. They are normally held out of contact with said guide faces by compression springs 38 mounted on rods 39 extending transversely from the ends of the brake shoes 36. Nuts 4U on said rods enable close adjustment of their normal spacing from the guide faces 34.

The described arrangement of several small hydraulic rams in line, gives the eifect of a large total ram area commensurate with a large brake shoe area, while permitting a convenient arrangement of the brake cylinders within the small space available for them.

The hydraulic power for operating'the brake rams 35 is obtained from compressed springs 4|. These tend to force apart the plates v42 fixed to the respective rams 43 of a pair of motor hydraulicvcylinders 44 mounted in the frame on bearers 45. Said motor cylinders are connected to the brake cylinders 33 by piping indicated by the dotted lines 46. The motor rams 43 are normally held fully extended from their cylinders 44 and the springs 4| correspondingly fully compressed, by pairs of open-topped hooks 41 which engage pins 48 extending transversely from projections 49 on the plates 42. Said hooks are also arranged to function as bearings on their respective pins 48. They extend from the stem 56 of a T shaped lever 56, 5|, 52; the arms 5|, 52 of which are lightened by being split. Light springs 53 hung from the cross beam 4, 4 sustain the weight of said T lever and hold the hooks 41 in engagement with the'pins 48. The T lever is thus retained in a fixed position, while being capable of downward and tilting movement against the resistance of the springs 53.

The T lever functions as a trigger for releasing the rams 43 and it will be seen that it can release the rams either by being bodily depressed, when it disengages both pairs of hooks 41 from their pins 48, or by being tilted, in which case itfulcrums about one pair of pins 48 and releases the other pair of pins, whereupon the pins that acted as a fulcrum readily slip off their hooks.

Upon the winding rope becoming overstressed the T lever is operated as` follows:

The tension of the rope is resisted by the cage suspending springs 25-which thus incidentally make the connection of the rop-e to the skip elastic. Rope tension materially above normal accordingly has the effect of so additionally compressing each such spring 25 that the capl 24 makes contact with the collar 28 and the pin 29 is subjected to shear. The resistance of said pin to shearing presents a safeguard against the brake being brought into action merely by say a tension surge in the rope; but more dangerous tensioning of the rope will cause the pin to shear through. The lower end 21a of the rod 21 is so adjusted lengthwise that at that moment it trips the T lever, thereby forcing the latter down and disengaging the hooks 41. The result is that the springs 4| thrust in the motor rams 43, in turn forcing out the brake rams 35 and pressing the brake shoes 36 against the sides 34 of the guides 2.

Also, upon the shearing of the pin, the levers 1, I8 are free to swing upward and release the collar |3. The whole king bolt assembly is thus released from the skip and with it the rope; and further stressing of the latter is avoided. f In the shown embodiment of the invention various additional agencies are provided for mov-- ing the T lever and thus releasing the rams 43 when an emergency occurs.

Attached to the cross head 6 is a pair of downwardly extending rods 54 formed with feet 55 to engage the split arms 5|, 52 of the T lever; the rods being adjustable relatively to the crosshead by means of nuts 56 in order to bring the feet 55 close to the lever arms 5i, 52. Accordingly in the event of the rope 8 breaking, without being subjected to stress much above normal; as sometimes happens; or if the king bolt breaks or loses its nuts '|2; or if a rising skip overruns the rope; or if the rope otherwise ceases to be tensioned, the compressed spring |5 extends and drives the rods 54 against the top of the T lever, thereby forcing the latter down and so applying the brakes.

ForV minimizing damage by overwinding the conveyance beyond its proper stopping place in theY head gear, the rods 21 are provided with upward extensions 21h arranged to strike beams such as 51 or other obstructions provided for that purpose in theV head gear. Upon this occurring the slidable rods 21 are forced down relatively to the skip as described, and the brakes are applied to hold the skip suspended without the rope.

Under certain circumstances it may be desirable to stop the skip at some point of its possible path, for instance to prevent its being lowered into a sump or in case the proper winding speed is exceeded on an upward journey. For such case there is provided the arm 58 extending from one end of the T lever and beyond the regular path i:

swept out by the rest of the skip structure. An obstruction is arranged in the path of this arm so as to engage the latter when the skip passes and thereby tilt the T lever, and thereby apply the brakes. such as 59 placed below the normal path of the arm 58 to prevent the skip travelling farther downward. Another kind of obstruction indicated by 66 may be a movable block which is projected into the path of the arm 58 as required, for instance a block which is thus projected by means of a governor device when the speed of the hoist drum exceeds a given limit.

Another way in which the T lever may be tripped is by means of a hand rope 6|, the lower end of which is passed into the cage when the conveyance is constructed for hoisting men.

For the sake of safety it is preferred to divide the whole hydraulic system into separate smaller units, so that if one unit fails, another or others are available to effect partial braking. In this case each motor cylinder 44 is connected only to the brake cylinders 33 at its side of the conveyance. Pipe connections for these conditions are indicated.

After the apparatus has operated to stop the skip, it is necessary to restore regular working conditions to provide a further store of energy by re-compression of the motor springs 4| and by releasing the brake shoes 36, For this purpose there is shown a drum 62 constituting a sump for brake liquid and containing two pumps 63, 63 each connected to its respective motor cylinder 44. By oscillating the pump handle, 64, liquid is forced into the cylinders 44, thereby projecting the rams 43 and compressing the springs 4| until the pins 48 can again be engaged by the hooks 41. Brake liquid is thereupon released from each hydraulic circuit and led into the sump 62 by opening the valves 65 until the The obstruction may be a block l 4 have withdrawn the. brakegshoessito their 'fully retracted position; the Avalves `65 being thereupn closed. The hoisting rope l8 has meanl" lhile been replaced or re-conn'ected and the 'pins 29, if sheared, replaced. i i A I Claim: p

l. The combination with `a hoist conveyance, of brake shoes, hydraulic cylinder and 'ram lsets operating sembrare shoes, a brera-unc icyiindsr and ram set connected 'to the brake 'sets to actuat them, 'a deio'rmd's'pring tending to force in the ram of the set, means locking said ram in its extended position and means rendered operative by abnormal hoisting conditions to unlock said locking means.

2. The combination of a hoist conveyance and a hoist rope by which the conveyance is suspended, conveyance braking means adapted to act on iixed guides, a trigger restraining the operation of said braking means and means responsive to excess tension of the rope for operating the trigger and thereby permitting the operation of the braking means.

3. The combination with a hoist conveyance, of energy storing means thereon, conveyance braking means, a hydraulic transmission actuated by release of the stored energy and in turn actuating the braking means, a trigger device for releasing the stored energy, and means responsive to change in the tension of the hoist rope for actuating the trigger device.

4. The combination with a hoist conveyance of means for releasably attaching the rope thereto, energy storing means thereon, conveyance braking means actuated by release of the stored energy, a trigger device for releasing the stored energy, and means responsive to excess tension in the rope for both releasing the rope and actuating the trigger device.

5. The combination with a hoist conveyance, of means for releasably attaching the rope thereto, energy storing means thereon, conveyance braking means actuated by release of the stored energy, means responsive to excess tension in the rope for both actuating the braking means and releasing the rope, and a selectively frangble stop device for resisting releaseof the rope.

6. The combination with a hoist conveyance, of means for releasably attaching the rope thereto, energy storing means thereon, conveyance braking means actuated by release of the stored energy, a trigger device for releasing the stored energy, means responsive to excess tension in the rope for both releasing the rope and actuating the trigger device, and a selectively frangible stop device for resisting release of the rope.

7. The combination with a hoist conveyance, of energy storing means thereon, conveyance braking means actuated by release of the stored energy, a king bolt for attachment of the hoist rope and supported for endwise movement, a spring tending to move it downward from its normal position, a rod extending downward from the king bolt, a` support on the king bolt, a pair of levers pivoted to the conveyance frame at me-dian points and having their adjacent ends resting on the support, springs upholding the outer ends vof the levers, rods arranged to be forced downward by downward movement of the outer ends of the levers, means responsive to excess tension in the king bolt for resisting such movement of the lever ends, all of said rods being arranged to actuate the braking means, and said levers being arranged to release the king bolt upon upward movement of their adjacent ends.

with ahoiist conveyance, of

8,` Theconibi'natioh 'energy storing means thereon, conveyance brakng means iactuated `by release 'of the stored endevice for releasing the stored bolt for attachment of the hoist for endwise movement, a

rope and "supported "springtending Lto move Vit downward from its norbmal posit1on, a rod exten-ding downward from fthe 'king bolt, 'a Support 'on the king bolt, a pair of iev'ersipivoted to the conveyance frame at median "points an'd 'h'av'ing their adjacentends resting on the support, springs upholding the outer ends of the levers, rods arranged to be forced downward by downward movement of the outer ends of the levers, means responsive to excess tension in the king bolt for resisting such movement of the lever ends, all of said rods being arranged to actuate the trigger device, and said levers being arranged to release the king bolt upon upward movement of their adjacent ends.

9. The combination with a hoist conveyance, of energy storing means thereon, conveyance braking means, a hydraulic transmission actuated by release of the stored energy and in turn actuating the braking means, a rope from which the conveyance is normally suspended, a king bolt for attachment of the hoist rope and supported for endwise movement, a spring tending tol move it downward from its normal position, a rod extending downward from the king bolt, a support on the king bolt, a pair of levers pivoted to the conveyance frame at median points and having their adjacent ends resting on the support, springs upholding the outer ends of the levers, rods arranged to be forced downward by downward movement of the outer ends of the levers, means responsive to excess tension in the king bolt for resisting such movement of the lever ends, all of said rods being arranged to actuate the braking means, and said levers being arranged to release the king bolt upon upward movement of their adjacent ends.

10'. The combination with a hoist conveyance, of energy storing means thereon, conveyance braking means actuated by release of the stored energy, a king bolt for attachment of the hoist rope and supported for endwise movement, a spring tending to move it downward from its normal position, a rod extending downward from the king bolt, a support on the king bolt, a pair of levers pivoted toy the conveyance frame at median points and having their adjacent ends resting on the support, springs upholding the outer ends of the levers, rods arranged to be forced downward by downward movement of the outer ends of the levers, pins provided by the rods actuated by the levers and arranged tobe sheared upon said rods being forced downward, all of the rods being arranged to actuate the braking means, and said levers being arranged to release the king bolt upon upward movement of their adjacent ends.

l1. The combination with a hoist conveyance of energy storing springs, movable plates between which the springs are compressed, pins carried by said plates and positioned transversely toy the direction of movement of the plates by the springs, a member hooked at each end for engaging said pins and thereby holding the plates together, conveyance braking means actuated by release of the energy stored by the springs, and means responsive to abnormal hoisting conditions for moving the hooked member and thereby releasing the pins from the hooks.

12. The combination with a hoist conveyance, of energy storing springs, movable plates between which the springs are compressed, pins carried by said plates and positioned transversely to the directio-n of movement of the plates by the springs, a member hooked at each end for engaging said pins and thereby holding the plates together, conveyance braking means, a hydraulic transmission actuated by the release of energy stored by the springs and in turn actuating the braking means, and means responsive to abnormal hoistaiszaegs ing conditions for moving the hooked member and thereby releasing the pins from the hooks.

13. The combination with a hoist conveyance of elongated brake shoes extending in the direc'- tion of the movement of the conveyance, a plurality of hydraulic cylinder and ram sets connected to and spaced along each shoe for operating said brake shoes, a hydraulic cylinder and ram set to actuate said brake sets, and means to actuate said cylinder and ram set.

FRANZ OTI'O JAECKEL. 

